Mechanisms of attention are critical for efficiently processing relevant information and avoiding distraction amidst a constant flood of sensory input. If these mechanisms are damaged, cognitive and social functioning can be severely impaired, as observed following brain damage (i.e., unilateral neglect syndrome), in developmental disorders (e.g., autism, ADHD), and in clinical populations (e.g., depression, schizophrenia). Understanding the mechanisms of attention in the healthy brain can significantly advance the development of improved therapies, targeted more precisely on the impaired aspect of attention. Decades of research have focused predominately on measuring voluntary and involuntary orienting in isolation. In much of everyday behavior, however, these systems are likely to interact, and the more severe attention deficits may be due to abnormal interactions between these attention systems. Furthermore, much previous research was driven by the assumption that voluntary and involuntary attention were simply two means of orienting the same "spotlight" of attention. Recent data, however, show that these types of attention affect processing in different ways and at different stages. Therefore, the interactions between these types of attention need to be considered at multiple levels of processing. The first main aim of the present grant is to investigate the interactions between voluntary attention and involuntary attention, using event-related potentials (ERPs) and functional MRI to identify the stages of processing and brain areas in which these interactions take place. The second main aim is to investigate the neural basis of distraction. Distraction is a specific instance of highly focused voluntary attention needing to overcome bottom-up influences on attention. Building upon our recent finding that new object distracters are uniquely effective in reducing target processing in early visual brain areas, we will investigate the degree to which other influences on attentional allocation (e.g., physical salience, face-processing, and memory) modulate the degree and level of distraction. The overall goal of this project is to elucidate the neural mechanisms of these multiple influences on attention and the interactions between them. This knowledge can be used to provide a new understanding of the aspects of attention that are dysfunctional in impaired individuals, and this can help in the development of new therapies directed at those systems.